Pulsing Brakes

Richard - could you define your meaning of 'pulses'?

Do you mean that the pedal feels a bit spongy when pressed or are you saying that when held stationary something is pushing the pedal back at you?

Does it only happen when you are braking with the wheels turning?

The front discs I assume are the originals and have not been repositioned on the hubs.

If by pulsing you mean a rhythmic pushing against your foot when braking, this will not be related to air in the system. It is usually due to damaged or distorted discs or drums. (could be only one, and could be front or back) JD

Sounds like warped rotors. Have them checked and/or recut. If replacing be sure to use proper tightening sequencing, star pattern, and tighten to the right torque spec.

Warped discs are quite probably a myth, I've met a few people personally who've cleaned "warped" discs and measured them with proper engineering gauges at small increments and found them to be within tolerance once they've been cleaned. Have a quick read of the following.

The first thing to do is to establish which brake is the troublesome one which involves clamping each flexible pipe in turn to see which one removes the fault when clamped whilst driving. As you have fitted stainless flexibles then this makes things a little difficult as you will damage them by clamping. You can disconnect and block each one in turn by refitting an old rubber flexi with the clamp on that (or a pair of mole grips) and carrying out the same test. Failing that just check that you have removed all the rusty lumps from the discs before fitting new pads but I think it's more likely that the new drums at the rear are not seated on the hubs properly since these are the only ones you have replaced, so take them off again and check. If you jack up each wheel in turn and spin them gently by hand you may be able to feel a tight spot on one of them to identify the problem. Finally you could also have a new drum which is faulty and you could find this by putting the old one back on to see what happens and, if so, send it back for a replacement.

HTH Martin

Hi All,

Thanks for all the replies. Pulsing - by that I mean that the brake pedal is pushing back at my foot as I apply pressure to it. It only does this when I brake hard. Gentle braking does not cause this. The pedal feels hard at all times.

The front pads were changed a couple of months ago and no problems then so they can be eliminated from the equation.

Noted that it is not likely to be air in the system. So that eliminates the new brake hoses too.

So the culprit has to be the rear braking system - New shoes and new drums at the same time as the hoses.

I've backed off the brake adjusters a couple of times and spun the wheels - they spin freely.

The conclusion then is that one of the rear brake drums is at fault - Action required then is to remove drums and check them for seating and any obvious distortion.

Finally is this an issue - If a drum is distorted is it necessary to replace it?

I'll report back when I've done the checking.

Many thanks for the comprehensive replies and pointers.

Regards

Richard